The 13 bit timer (ie, timer mode 0) is rarely used these days in 8051 uc based applications. The only reason there is such a timer mode is to maintain compatibility with its predecessor the Intel 8048 microcontroller (Intel MCS 8048 family).
The 8048 had a divide by 32 prescaler, so the Intel guys set up the mode 0 of 8051 timer with lower five bits of TLx register acting as divide by 32 element which is then cascaded to the 8 bits of THx to give a 13 bit timer.
http://goo.gl/AZ94XG
http://en.wikipedia.org/wiki/Intel_MCS-48
The 8048 had a divide by 32 prescaler, so the Intel guys set up the mode 0 of 8051 timer with lower five bits of TLx register acting as divide by 32 element which is then cascaded to the 8 bits of THx to give a 13 bit timer.
Microcontroller: Features and Applications By D. S. Yadav, Arun Kumar Singh
http://goo.gl/AZ94XG
http://en.wikipedia.org/wiki/Intel_MCS-48
No comments:
Post a Comment